Due to the limited reserves of fossil fuels and worries about emission of greenhouse gasses there is an increasing focus on using renewable energy sources such as plant material.
A vast number of processes of producing fermentation products, especially biofuel products such as ethanol and butanol, by fermentation of sugars derived from starch-containing and/or lignocellulose-containing material are known in the art.
However, production of such fermentation products from plant materials is still too costly. Therefore, there is a need for providing processes that can reduce production costs.